Phenyl propane derivatives as antibiotics and lipoxygenase inhibitors

ABSTRACT

The invention relates to phenyl propane derivatives of the general formulae: ##STR1## or their mixtures, in which R 1  and R 2  are a branched or straight-chained alkyl residue of the general formula C n  H 2n+1  with n=1-18, for use as a therapeutic agent.

In recent times the use of natural materials in medicine has become increasingly important. Such analogue natural materials must however be simple and cost-effective to produce, and their therapeutic action must at least approximate to or even entirely equate to that of synthetically-produced preparations. Until now, these requirements have been satisfied by very few natural preparations.

Proceeding from this basis it is the object of the present invention to propose therapeutic active ingredients which are derived from natural materials, these analogue natural materials having to be capable of manufacture by simple and cost-effective methods. The therapeutic action is to correspond approximately to that of synthetic preparations.

This object is achieved by the phenyl propane derivatives defined in more detail in Patent claim 1. Patent claims 4 to 6 show preferred uses of the phenyl propane derivates, while Patent claims 6 and 7 feature the use of the phenyl propane derivates as medicine.

Surprisingly, it has become apparent that the phenyl propane derivates (phenyl proponoids) contained in coreopsis types (asteraceae), with their unusual structural features, are outstandingly suitable as a therapeutic active ingredient, particularly as an antibacterial agent. The phenyl propane derivates according to the invention are diesters of 1'-hydroxyeugenol or diesters of (epoxy)-E/Z-coniferyl alcohols. The occurrence of the diesters of 1'-hydroxyeugenol and of the epoxy-Z coniferyl alcohol (natural substances) appears to be largely restricted to the species coreopsis. Until now only the diacetate of 1'-hydroxyeugenol has been found outwith the species coreopsis in alpinia galanga (zingiberaceae).

It is particularly preferred if the alkyl residue R1 or R2 of the ester group is either methyl, isopropyl, 1-methylpropyl or isobutyl. Quite particularly preferred are the phenyl propane derivates with R1 isopropyl and R2 methyl, isopropyl, 1-methylpropyl or isobutyl.

The phenyl propane derivates described above have surprisingly proved to be extensively selectively-acting antibacterial materials. They are capable of selectively combating problem germs such for example as staph. epidermidis, staph. haemolyticus, or acinetobacter calcoaceticus. In this respect it has become apparent that the antibacterial effect is in part better than for example that of the known antibiotic Cefuroxim®.

Apart from this use as antibiotics, the abovenamed, more extensively described phenyl propane derivates are also suitable for inhibiting the activity of 5-lipoxygenase in human leucocytes. That is, 5-lipoxygenase catalyses the first two reaction stages of the conversion of arachidonic acid to the biologically highly-active leucotrienes B₄, C₄, D₄ and E₄. Leucotrienes are important mediators in infective and allergenic reactions. There is therefore great interest in developing corresponding inhibitors which suppress the activity of 5-lipoxygenase. It is now surprisingly revealed that the phenyl propane derivates described above are also suitable for inhibition of the 5-lipoxygenase activity in basophile leukaemia cells of the rat, and in human leucocytes.

Accordingly, by means of the phenyl propane derivates proposed according to the invention, there is proposed a new therapeutic active ingredient with interesting properties in various fields of application.

The phenyl propane derivates may thus be used in medicines with carrier, additive and accessory agents known per se.

The phenyl propane derivates according to the invention may in this case preferably be applied percutaneously, per orem or rectally. A further field of application is the coating of catheters.

In the case of percutaneous application, the phenyl propane derivates are preferably used in the form of powders, ointments, solutions or occlusion dressings. This is advantageous as, after penetration of the skin (hair follicles, injuries) or of the mucous membrane, staphylococci show a tendency to remain at the locus of penetration, causing local infections involving the formation of pus.

For per-orem or rectal application, suitable uses are in the form of pills, tablets, capsules, solutions, emulsions, suppositories, rectal capsules or microclysms. This form of application is particularly suitable in an ulcerous staphylococcal endocarditis which frequently occurs after heart operations.

A factor to be specially emphasised in the phenyl propane derivates according to the invention is their high degree of effectiveness against coagulase-negative staphylococci. These have the capacity to adhere to plastics (e.g. catheters), and there to multiply. Thus they can be washed into the bloodstream and cause sepsis-type syndromes. Coating of catheters, for example with 1'-hydroxyeugenol derivates, is advantageous as prophylaxis of such complications. Chemical bonding of the molecules to the surface of the plastics is possible with almost no loss of effectiveness. Adhesion to the catheter may also be carried out, as the intensely lipohilic substances have no affinity with the mostly hydrophilic body fluids.

A particularly advantageous factor in the phenyl propane derivates proposed according to the invention is that they are simple and cost-effective to manufacture. A prescription for synthesis of the phenyl propane derivates according to the invention is for example indicated in Z. Naturforsch. 44C, 7-11 (1989). Further sources are cited in this publication, in which further such derivates and corresponding manufacturing instructions are described.

The invention will be described in more detail in the following with reference to the use of phenyl propane derivates as a selective antibacterial agent. The invention may best be understood by referring to the following detailed description and accompanying FIGS. 1-5 which illustrate the invention.

The only material which has until now become known from the literature relates to the utilisation of eugenols, i.e. compounds structurally different from the proposed diesters of 1-hydroxyeugenol and (epoxy)-E/Z-coniferyl alcohols, in conjunction with other agents, as an antiseptic or antibacterial agent.

Thus for example it is proposed in U.S. Pat. No. 3,219,526 to use eugenol in combination with NMSE (5-nitro-2-methylfurfuryl ether). Particular reference is there made to the fact that, clearly due to the combination of these two active ingredients, a special effect is achieved in relation to the antiseptic action. Other proposals relating to the use of eugenols as an antibacterial and antiseptic agent arise from other combinations with other active ingredients. Thus for example, in DE 39 08 527 a disinfectant is also described, which contains eugenol and other active ingredients.

It was therefore totally surprising and unexpected that the phenyl propane derivates according to the invention should on their own have such surprising properties as regards their antibacterial activity.

The phenyl propane derivates given in FIG. 1 are particularly suitable as an antibacterial agent.

As a test of their antibacterial effect, agar plates with a diameter of 10 cm were used, each plate being provided with 10 ml of agar (Caso-Agar or Muller-Hinton agar). The various bacterial suspensions were respectively applied to 10⁶ KBE per ml of nutrient solution. Of this, 0.3 μl in each case were applied by multipoint inoculator to the agar plates. Parent solutions of various phenyl propane derivates were produced in dichloromethane. Aliquot portions were then removed from the parent solutions, the solvent blown under N₂ and dissolved in 100 μl (1%) DMSO. The DMSO solution was then added to 10 ml of liquid agar. 1 mM of substance corresponded to approximately 3-4 mg of substance per agar plate. Growth of the bacteria was inhibited only after addition of 7 DMSO. The minimum inhibiting concentration (MHK) was determined, i.e. the lowest concentration of the substance which inhibited the bacterial growth (macroscopically, no further growth could be detected).

In a widely-applied screening, firstly the phenyl propane derivates of the general formula I with R₁ with isopropyl and R₂ methyl, isopropyl, isobutyl and 1-methylpropyl were tested in comparison to eugenol and phenol for their bacteriostatic power (see Tables 1 and 2). The eugenol derivate with R₂ methyl is entered in Tables 1 and 2 as Eu2, that with R₂ isopropyl as Eu3, that with R₂ isobutyl as Eu4 and that with R₂ 1-methylpropyl as Eu5. Of particular interest is the action of the substances on the staphylococci. Substances Eu2-Eu5 above all proved highly effective against various coagulase-negative staphylococci. Of the 5 coagulase-negative staphylococci, only staph. warneri and staph. simulans were resistant to 1'-hydroxyeugenol derivates. On the other hand, staph. haemolyticus and staph. capitis were extremely well controlled by Eu2-Eu5. The MHK values determined give evidence of outstanding antibacterial action of these substances.

Of interest is the comparison with Cefuroxim, a cephalosporin antibiotic of the second generation (cf. Table 2). In the case of staph. haemolyticus the MHK value for Cefuroxim is above 190 μM, and thus clearly above the MHK values of Eu2-Eu5. Therefore this is the rare case in which a natural vegetable material is clearly more effective in antimicrobial terms than a medically established antibiotic. Racemic compounds were used in the experiments. The optically pure enantiomers however reveal the same effectiveness.

The epoxidised E- and Z-coniferyl alcohol derivates (general formulae IV and V) are just as antibacterially potent as the 1'-hydroxyeugenol derivates (cf. Tables 3 and 4). In this case Z-Co1epox identifies the epoxidised Z-coniferyl alcohol with R₂ methyl, and correspondingly for R₂ isopropyl (Z-Co2epox) and for R₂ isobutyl (Z-Co3epox). The E-coniferyl alcohol derivates are correspondingly identified. Interestingly, they also revealed the same qualitative profile of effectiveness, i.e. they were antimicrobially effective against the same bacteria. They were more effective with staph. aureus, and controlled the coagulase-negative staphylococci just as well as the 1'-hydroxyeugenol derivates.

                                      TABLE 1                                      __________________________________________________________________________     Determination of MHK by Agar Dilution in mM                                    Substance       Eu2 Eu3 Eu4 Eu5 Eugenol                                                                            Phenol                                     __________________________________________________________________________     Acinet. calcoac.                                                                               <0.75                                                                              <0.75                                                                              12  >12 2   11                                         Bac. cereus ATCC 4342                                                                          <0.75                                                                              1.5 >12 >12 2   15                                         B. subtilis ATCC 6659                                                                          <0.75                                                                              >12 >12 >12 3   14                                         Coryn. dipht. ATCC 10648                                                                       3   12  >12 >12 2   10                                         E. coli CL      >12 >12 >12 >12 4   16                                         E. coli ATCC 43822                                                                             >12 >12 >12 >12 4   18                                         E. coli NCTC 8196                                                                              >12 >12 >12 >12 4   18                                         Klebs. pneu. ATCC 4356                                                                         >12 >12 >12 >12 3   18                                         Microc. luteus  >12 >12 >12 >12 3   10                                         Ps. aerug. CL   >12 >12 >12 >12 7   10                                         Ps. aerug. ATCC 15442                                                                          >12 >12 >12 >12 7   10                                         Ps. diminuta ATCC 19146                                                                        >12 >12 >12 >12 2   10                                         Ps. maltophilla >12 >12 >12 >12 3   10                                         Sarcina lutea ATCC 9341                                                                        3   1.5 12  12  4   25                                         Serratia marcescens                                                                            >12 >12 >12 >12 4   12                                         Shig. flexneri CL                                                                              >12 >12 >12 >12 3   12                                         Shig. flexneri ATCC 25929                                                                      >12 >12 >12 >12 3   11                                         Salm. typhi ATCC 6599                                                                          >12 >12 >12 >12 3   12                                         Salm. typhimurium ATCC 13311                                                                   >12 >12 >12 >12 4   19                                         Staph. aureus CL                                                                               <0.75                                                                              <0.75                                                                              12  >12 4   21                                         Staph. aureus clp 53154                                                                        <0.75                                                                              <0.75                                                                              6   >12 4   24                                         Staph. aureus 6538 Kiel                                                                        <0.75                                                                              <0.75                                                                              12  >12 3   19                                         Staph. aureus NCTC 4163                                                                        <0.75                                                                              <0.75                                                                              12  >12 4   19                                         Strep. faeclum DSG 8582                                                                        >12 >12 >12 >12 3   >25                                        Strep. faeclum clp 5855                                                                        >12 >12 >12 >12 4   >25                                        Strep. faecalis ATCC 6057                                                                      12  12  >12 >12 3   >25                                        Xantho. maltophil.                                                                             >12 >12 >12 >12 3   10                                         Strep. with alpha haemolysis                                                                   12  12  >12 >12 3   21                                         Strep. pyo Gr. A beta haemolysis                                                               6   12  >12 >12 2   17                                         Strep. with beta haemolysis                                                                    6   12  >12 >12 2   21                                         Enterococci with gamma haeomolysis                                                             >12 >12 >12 >12 /   /                                          __________________________________________________________________________

                                      TABLE 2                                      __________________________________________________________________________     Determination of MHK by Agar Dilution                                                               Eu2   Eu3   Eu4   Eu5   Cefuroxim                                     Isolated from:                                                                          MHK in uM                                                                            MHK in uM                                                                            MHK in uM                                                                            MHK in uM                                                                            MHK in uM                         __________________________________________________________________________     Staph. warneri                                                                             blood culture                                                                           >3000 >3000 >3000 >3000 1                                 Staph. epidermidis                                                                         blood culture                                                                           94    47    375   23    6                                 Staph. epidermidis                                                                         blood culture                                                                           94    47    375   23    6                                 Staph. epidermidis                                                                         blood culture                                                                           188   188   1500  188   0.4                               Staph. epidermidis                                                                         blood culture                                                                           188   188   1500  188   1                                 Staph. simulans                                                                            A5689    >3000 >3000 >3000 >300  6                                 Staph. epidermidis                                                                         catheter tip                                                                            188   47    750   23    1                                 Staph. epidermidis                                                                         skin     188   47    750   47    1                                 Staph. haemolyt.                                                                           skin     47    23    47    12    >190                              Staph. capitis                                                                             blood culture                                                                           375   188   3000  >3000 0.4                               Staph. epidermidis                                                                         catheter tip                                                                            188   94    375   47    1                                 Staph. epidermidis                                                                         3-way tap                                                                               188   94    3000  94    1                                 Staph. epidermidis                                                                         catheter tip                                                                            188   94    188   23    6                                 Staph. haemolyt.                                                                           catheter tip                                                                            188   94    188   47    >190                              Staph. epidermidis                                                                         skin     188   47    188   23    1                                 Staph. haemolyt.                                                                           catheter tip                                                                            188   23    47    23    >190                              Staph. aureus                                                                              throat   375   188   >3000 >3000 6                                 Staph. aureus                                                                              trachea  750   750   >3000 >3000 6                                 Staph. aureus                                                                              wound    375   188   3000  >3000 6                                 Staph. aureus                                                                              pus      375   188   >3000 >3000 6                                 Staph. aureus                                                                              operation scar                                                                          375   188   >3000 >3000 3                                 Staph. aureus                                                                              pleura   750   375   >3000 >3000 6                                 Staph. aureus                                                                              skin     750   188   >3000 >3000 6                                 Staph. aureus                                                                              ear      750   750   >3000 >3000 3                                 Staph. aureus                                                                              trachea  750   750   >3000 >3000 3                                 Staph. aureus                                                                              conjuctiva                                                                              375   188   >3000 >3000 3                                 Staph. aureus                                                                              throat   188   188   3000  >3000 6                                 Staph. aureus                                                                              amputation wound                                                                        188   94    3000  >3000 3                                 Staph. aureus                                                                              ulcus    375   375   >3000 >3000 3                                 Staph. aureus                                                                              throat   750   375   >3000 >3000 3                                 Staph. aureus                                                                              eye      188   94    3000  >3000 6                                 Staph. aureus                                                                              trachea  375   188   3000  >3000 6                                 Staph. aureus                                                                              conjunctiva                                                                             375   375   >3000 >3000 6                                 Staph. aureus 6538 Kiel                                                                             375   188   12000 >12000                                                                               3                                 Staph. aureus NCTC 4163                                                                             750   375   12000 >12000                                                                               6                                 Staph. aureus clp 53154                                                                             375   94    6000  >12000                                                                               3                                 __________________________________________________________________________

                                      TABLE 3                                      __________________________________________________________________________     Determination of MHK by Agar Dilution                                                         Z-Co 1 pox                                                                           E-Co 1 epox                                                                          Z-Co2epox                                                                            E-Co2epox                                                                            Z-Co3epox                                                                            E-Co3epox                         Substance      MHK in uM                                                                            MHK in uM                                                                            MHK in uM                                                                            MHK in uM                                                                            MHK in uM                                                                            MHK in uM                         __________________________________________________________________________     Acinet. calcoac.                                                                              375   375   3000  188   3000  6000                              Bac. cereus ATCC 4342                                                                         1500  188   >6000 <94   >6000 188                               B. subtilis ATCC 6659                                                                         1500  188   1500  <94   750   188                               Coryn. dipht. ATCC 10648                                                                      >6000 >6000 >6000 >6000 >6000 >6000                             E. coli CL     >6000 >6000 >6000 >6000 >6000 >6000                             E. coli ATCC 43822                                                                            >6000 >6000 >6000 >6000 >6000 >6000                             E. coli NCTC 8196                                                                             >6000 >6000 >6000 >6000 >6000 >6000                             Klebs. pneu. ATCC 4356                                                                        >6000 >6000 >6000 >6000 >6000 >6000                             Micrococ. luteus                                                                              >6000 >6000 >6000 >6000 >6000 >6000                             Ps. aerug. CL  >6000 >6000 >6000 >6000 >6000 >6000                             Ps. aerug. ATCC 15442                                                                         >6000 >6000 >6000 >6000 >6000 >6000                             Ps. diminuta ATCC 19146                                                                       1500  3000  >6000 >6000 >6000 >6000                             Ps. maltophilla                                                                               >6000 >6000 >6000 >6000 >6000 >6000                             Sarcina lutea ATCC 9341                                                                       1500  6000  <94   750   <94   <94                               Serratia marescens                                                                            >6000 >6000 >6000 >6000 >6000 >6000                             Shig. flexneri Cl                                                                             >6000 >6000 >6000 >6000 >6000 >6000                             Shig. flexneri ATCC 25929                                                                     >6000 >6000 >6000 >6000 >6000 >6000                             Salm. typhi ATCC 6599                                                                         >6000 >6000 >6000 >6000 >6000 >6000                             Salm. typhimurium ATCC 13311                                                                  >6000 >6000 >6000 >6000 >6000 >6000                             Staph. aureus CL                                                                              <94   <94   <94   <94   <94   <94                               Staph. aureus clp 53154                                                                       94    47    94    94    94    47                                Staph. aureus 6538 Kiel                                                                       94    47    94    94    <47   47                                Staph. aureus NCTC 4163                                                                       188   94    188   94    94    47                                Staph. warneri Nr. 16                                                                         >6000 >6000 >6000 >6000 >6000 >6000                             Staph. epidermidis Nr. 17                                                                     188   94    188   94    94    94                                Staph. simulans Nr. 173                                                                       >6000 >6000 >6000 >6000 >6000 >6000                             Staph. epidermidis Nr. 187                                                                    188   94    188   94    94    94                                Staph. haemolyt. Nr. 236                                                                      94    47    94    94    <47   23                                Strep. faeclum DSG 8582                                                                       >6000 >6000 >6000 >6000 >6000 >6000                             Strep. faeclum clp 5855                                                                       >6000 >6000 >6000 >6000 >6000 >6000                             Strep. faecalis ATCC 6057                                                                     >6000 >6000 >6000 >6000 >6000 >6000                             Xantho. maltophil.                                                                            >6000 >6000 >6000 >6000 >6000 >6000                             Strep. with alpha haeomolysis                                                                 6000  1500  6000  1500  3000  3000                              Strep. Gr. A   >6000 >6000 >6000 >6000 >6000 >6000                             Strep. with beta haemolysis                                                                   >6000 >6000 >6000 >6000 >6000 >6000                             Enterococci with gamma haemol.                                                                >6000 >6000 >6000 >6000 >6000 >6000                             __________________________________________________________________________

                                      TABLE 4                                      __________________________________________________________________________     Determination of MHK by Agar Dilution                                                               ZCo1epox                                                                             ECo1epox                                                                             ZCo2epox                                                                             ECo2epox                                                                             ZCo3epox                                                                             ECo3epox                                                                             Cefuroxim             Substance            MHK in uM                                                                            MHK in uM                                                                            MHK in uM                                                                            MHK in uM                                                                            MHK in uM                                                                            MHK in                                                                               MHK in                __________________________________________________________________________                                                              uM                    Staph. warneri                                                                             blood culture                                                                           >375  >375  >375  375   94    94    1                     Staph. epidermidis                                                                         blood culture                                                                           188   188   188   188   188   94    6                     Staph. epidermidis                                                                         blood culture                                                                           375   375   188   188   94    94    6                     Staph. epidermidis                                                                         blood culture                                                                           375   375   375   375   188   188   0.4                   Staph. epidermidis                                                                         blood culture                                                                           375   375   375   375   188   188   1                     Staph. simulans                                                                            A5689    >375  >375  >375  >375  188   >375  6                     Staph. epidermidis                                                                         trachea  375   375   188   375   188   188   1                     Staph. epidermidis                                                                         skin     188   188   188   375   94    94    1                     Staph. haemolyt.                                                                           skin     47    23    47    23    47    12    >190                  Staph. capitis                                                                             blood culture                                                                           188   94    188   94    47    23    0.4                   Staph. epidermidis                                                                         catheter tip                                                                            375   375   375   375   188   188   1                     Staph. epidermidis                                                                         3-way tap                                                                               375   375   375   375   188   188   1                     Staph. epidermidis                                                                         catheter tip                                                                            188   188   188   188   94    94    6                     Staph. haemolyt.                                                                           catheter tip                                                                            94    47    188   94    47    23    190                   Staph. epidermidis                                                                         skin     375   375   188   375   188   188   1                     Staph. haemolyt.                                                                           catheter tip                                                                            188   47    94    94    47    47    >190                  Staph. aureus                                                                              throat   375   94    375   188   94    94    6                     Staph. aureus                                                                              trachea  >375  94    >375  188   188   94    6                     Staph. aureus                                                                              wounds   375   47    375   94    188   47    6                     Staph. aureus                                                                              pus      375   188   375   188   188   94    6                     Staph. aureus                                                                              operation scar                                                                          375   188   188   188   188   188   3                     Staph. aureus                                                                              pleura   >375  188   375   375   188   94    6                     Staph. aureus                                                                              skin     >375  188   >375  375   94    188   6                     Staph. aureus                                                                              ear      >375  94    375   94    94    47    3                     Staph. aureus                                                                              trachea  >375  94    >375  375   188   188   3                     Staph. aureus                                                                              conjunctiva                                                                             >375  94    375   188   188   94    3                     Staph. aureus                                                                              throat   375   188   375   188   188   94    6                     Staph. aureus                                                                              amputation wound                                                                        375   47    375   188   188   47    3                     Staph. aureus                                                                              ulcus    >375  94    375   375   188   94    3                     Staph. aureus                                                                              throat   >375  47    >375  188   188   188   3                     Staph. aureus                                                                              eye      >375  47    375   94    94    47    6                     Staph. aureus                                                                              trachea  375   94    375   188   94    94    6                     Staph. aureus                                                                              conjunctiva                                                                             >375  94    375   375   94    94    6                     Staph. aureus 6538 Kiel                                                                             188   47    188   47    47    47    3                     Staph. aureus NCTC 4163                                                                             375   188   375   188   94    47    6                     Staph. aureus clp 53154                                                                             188   47    188   94    94    47    3                     __________________________________________________________________________ 

We claim:
 1. An agent for combating bacterial infections containing phenyl propane derivatives of the general formulae: ##STR2## or their mixtures, in which R₁ and R₂ are independently branched or straight chained alkyl residue of the general formula C_(n) H_(2n+1) where n is 1-18, with the proviso that, in Formula I, R₁ and R₂ are not simultaneously CH₃, for use as a therapeutic agent.
 2. An agent according to claim 1, wherein R₁ is methyl, isopropyl or 1-methylpropyl.
 3. An agent according to claim 1 wherein R₁ and R₂ are each independently methyl, isopropyl, isobutyl or 1-methylpropyl.
 4. An agent according to claim 1 wherein R₂ is methyl, isopropyl, isobutyl or 1-methylpropyl.
 5. An agent according to claim 1, 2, 3, or 4 wherein R₁ is isopropyl and R₂ is methyl, isopropyl, isobutyl or 1-methylpropyl. 